High Intensity Supersonic Molecular Beam Apparatus

Campargue, R.

doi:10.1063/1.1718676

Cited by 71 publications

(27 citation statements)

References 2 publications

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“…This is essential to form a stable distribution of Aun-Kr complexes. The set-up follows the design of Campargue [44] with a moderate vacuum (0.1 mbar) in the source chamber obtained by a mechanical booster / rotary vane pump combination (Edwards EH1200/E2M80), differential pumping stage (10 -4 mbar), and a high vacuum stage (10 -6 mbar) that contains a reflectron time-of-flight mass spectrometer (Jordan TOF Products, Inc.); the latter two are pumped by turbomolecular pumps. Gold clusters are produced by pulsed (10 Hz) laser ablation of a solid gold target in a continuous stream of a carrier gas, consisting of 1.5% krypton in helium.…”

Section: Methodsmentioning

confidence: 99%

Far-IR Spectra of Small Neutral Gold Clusters in the Gas Phase

Gruene

Butschke

Lyon

et al. 2014

Zeitschrift Für Physikalische Chemie

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Abstract. Vibrational spectra of small neutral gold clusters containing up to 8 Au atoms are measured in the far-infrared (46-222 cm -1 ) via photodissociation of their complexes with krypton atoms. Comparisons with calculated IR spectra for bare Aun clusters using density functional theory allow for structural assignment. For these small sizes, all clusters are found to be planar and of comparably high symmetry. For Au6 no data is available, as this cluster size is not detected in the photoionization mass spectra due to its high ionization energy. The structures assigned are for n = 4: rhombus (D2h); 5: trapezoid (C2v); 7: edge-capped triangle (Cs), 8: 4-fold edge-capped square (D4h).

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Section: Methodsmentioning

confidence: 99%

Far-IR Spectra of Small Neutral Gold Clusters in the Gas Phase

Gruene

Butschke

Lyon

et al. 2014

Zeitschrift Für Physikalische Chemie

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“…Collision with the background gas causes the expansion to end in strong shock waves after 20-30 mm, called a Campargue expansion (17). To extract a steady beam from the source chamber, a conical skimmer is placed at a distance of 10-15 mm from the nozzle.…”

Section: Methodsmentioning

confidence: 99%

Magnetic nanodots from atomic Fe: Can it be done?

Sligte

Bosch

Smeets

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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Laser focusing of Fe atoms offers the possibility of creating separate magnetic structures on a scale of 10 nm with exact periodicity. This can be done by using the parabolic minima of the potential generated by a standing light wave as focusing lenses. To achieve the desired 10-nm resolution, we need to suppress chromatic and spherical aberrations, as well as prevent structure broadening caused by the divergence of the incoming beam. Chromatic aberrations are suppressed by the development of a supersonic Fe beam source with speed ratio S ‫؍‬ 11 ؎ 1. This beam has an intensity of 3 ؋ 10 15 atoms sr ؊1 s ؊1 . The spherical aberrations of the standing light wave will be suppressed by aperturing with beam masks containing 100-nm slits at 744-nm intervals. The beam divergence can be reduced by application of laser cooling to reduce the transverse velocity. We have constructed a laser system capable of delivering over 500 mW of laser light at 372 nm, the wavelength of the 5 D4 3 5 F5 atomic transition of 56 Fe we intend to use for laser cooling. Application of polarization spectroscopy to a hollow cathode discharge results in a locking system holding the laser continuously within 2 MHz of the desired frequency.

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“…As a result strong shock waves appear at the boundaries of the Camparguetype expansion [15] and a conical skimmer has to be used to extract an atomic beam on the center line carefully without excessive loss of beam intensity. Inside the skimmer tip the beam is attenuated according to Beer's law, i.e., an exponential decrease with an exponent scaling with the local inverse Knudsen number Kn −1 .…”

Section: Seeded Supersonic Expansionsmentioning

confidence: 99%